scsi: core: Add a dma_alignment field to the host and host template

Get drivers out of the business of having to call the block layer DMA
alignment limits helpers themselves.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240409143748.980206-8-hch@lst.de
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

4 files changed, 12 insertions, 13 deletions

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 4f495a41ec4a..a67a98bd7ae2 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -478,6 +478,12 @@ struct Scsi_Host *scsi_host_alloc(const struct scsi_host_template *sht, int priv
 	else
 		shost->max_segment_size = BLK_MAX_SEGMENT_SIZE;
 
+	/* 32-byte (dword) is a common minimum for HBAs. */
+	if (sht->dma_alignment)
+		shost->dma_alignment = sht->dma_alignment;
+	else
+		shost->dma_alignment = 3;
+
 	/*
 	 * assume a 4GB boundary, if not set
 	 */
diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 8e14cea15f98..60688f18fac6 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -943,6 +943,7 @@ iscsi_sw_tcp_session_create(struct iscsi_endpoint *ep, uint16_t cmds_max,
 	shost->max_id = 0;
 	shost->max_channel = 0;
 	shost->max_cmd_len = SCSI_MAX_VARLEN_CDB_SIZE;
+	shost->dma_alignment = 0;
 
 	rc = iscsi_host_get_max_scsi_cmds(shost, cmds_max);
 	if (rc < 0)
@@ -1065,7 +1066,6 @@ static int iscsi_sw_tcp_slave_configure(struct scsi_device *sdev)
 	if (conn->datadgst_en)
 		blk_queue_flag_set(QUEUE_FLAG_STABLE_WRITES,
 				   sdev->request_queue);
-	blk_queue_dma_alignment(sdev->request_queue, 0);
 	return 0;
 }
 
diff --git a/drivers/scsi/qla2xxx/qla_os.c b/drivers/scsi/qla2xxx/qla_os.c
index 6a1900e96a5a..fcb06df2ce4e 100644
--- a/drivers/scsi/qla2xxx/qla_os.c
+++ b/drivers/scsi/qla2xxx/qla_os.c
@@ -1957,9 +1957,6 @@ qla2xxx_slave_configure(struct scsi_device *sdev)
 	scsi_qla_host_t *vha = shost_priv(sdev->host);
 	struct req_que *req = vha->req;
 
-	if (IS_T10_PI_CAPABLE(vha->hw))
-		blk_queue_update_dma_alignment(sdev->request_queue, 0x7);
-
 	scsi_change_queue_depth(sdev, req->max_q_depth);
 	return 0;
 }
@@ -3575,6 +3572,9 @@ skip_dpc:
 		    QLA_SG_ALL : 128;
 	}
 
+	if (IS_T10_PI_CAPABLE(base_vha->hw))
+		host->dma_alignment = 0x7;
+
 	ret = scsi_add_host(host, &pdev->dev);
 	if (ret)
 		goto probe_failed;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index f1936f98abe3..26b51406c477 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1985,15 +1985,8 @@ void scsi_init_limits(struct Scsi_Host *shost, struct queue_limits *lim)
 	lim->seg_boundary_mask = shost->dma_boundary;
 	lim->max_segment_size = shost->max_segment_size;
 	lim->virt_boundary_mask = shost->virt_boundary_mask;
-
-	/*
-	 * Set a reasonable default alignment:  The larger of 32-byte (dword),
-	 * which is a common minimum for HBAs, and the minimum DMA alignment,
-	 * which is set by the platform.
-	 *
-	 * Devices that require a bigger alignment can increase it later.
-	 */
-	lim->dma_alignment = max(4, dma_get_cache_alignment()) - 1;
+	lim->dma_alignment = max_t(unsigned int,
+		shost->dma_alignment, dma_get_cache_alignment() - 1);
 
 	if (shost->no_highmem)
 		lim->bounce = BLK_BOUNCE_HIGH;